# Two simple questions

1. Oct 29, 2012

### Crazymechanic

First , elementary particles traveling through vacuum , do they experience any loss of kinetic energy or whatever or are they "unharmed", unchanged while traveling in vacuum?
my guess would be for the second one.

And the other question let me put it this way.
Imagine there is a nuclear fusion reaction and the elementary particles are sitting on a merry-go-round that's spins pretty fast in a vacuum , do the high energy neutrons that come out , do they fly in any direction or are they traveling along the sides away from the merry-go-round because of tangential forces acting on them so that they fly that direction or do they still go equally every direction? Or is this dependent of the tangential velocity?

Thanks

2. Oct 30, 2012

### tiny-tim

Hi Crazymechanic!
"unharmed"
Sorry, I don't follow this â€¦

why would there be any forces on them, tangential or otherwise?

(If you mean, is the neutron velocity distribution affected by the velocity of the initial particles, the answer is yes, whether that velocity is circular or linear)

3. Oct 30, 2012

### Crazymechanic

Well i was thinking of terms like the metal ball i was speaking about when mentioning the tangential velocity the metal ball flies off to that direction or feels stress to that direction does neutron would do the same being part of the gas or whatever that is spun in a centrifuge where you experience tangential velocity?

4. Oct 30, 2012

### tiny-tim

the gas has tangential velocity, so the neutron distribution will be biased towards that velocity

5. Oct 31, 2012

### Crazymechanic

Thanks just the answer I was looking for

6. Oct 31, 2012

### manojr

Mostly "unharmed". Visitors who come from very very long distance are observed to be red shifted.

7. Oct 31, 2012

### Crazymechanic

and that is done by gravity i guess so the only thing that can alter or change a particles way through vacuum is gravity am I correct stating this?

8. Oct 31, 2012

### tiny-tim

gravity will do it, but i think manojr was referring to redshift caused by expansion of the universe

9. Oct 31, 2012

### JustinRyan

The deformation of space can effect the path & energy of a particle travelling through it. This can include gravitational fields. Redshift is mostly caused by the stretching of space due to the expansion of the universe.

10. Nov 1, 2012

### Lsos

If a particle is charged, electromagnetic forces can also accelerate it.